Burner and ignition controller with shut-down



NOV. 13, 1934. HENMNG 1,980,525

BURNER AND IGNITION CONTROLLER WITH SHUT-DOWN Filed Nov. 16, 1931 Patented Nov. 13, 1934 PATENT OFFICE BURNER AND IGNITION CONTROLLER WITH SHUT-DOWN Malcolm E. Henning, Des Moines, Iowa, assignor to Penn Electric Switch 00., Des Moines, Iowa,

a corporation of Iowa Application November 16, 1931, Serial No. 57 5,278

2 Claims.

One object of my present invention is to provide a shut-down feature consisting of mechanism, which is simple, durable and inexpensive to manufacture, for connection with a burner and ignition controller.

A further object is to provide shut-down mechanism for use in connection with a burner and ignition controller of the type shown in my copending application, Serial No. 566,838, filed October 5, 1931.

More particularly, it is my object to provide in connection with "aburner and ignition controller in which a burner is controlled by a burner switch and the ignition of the burner is controlled by an ignition switch, a means for preventing the ignition switch from returning from open circuit to closed circuit position while the burner switch is still in closed circuit position.

A further object is to provide a means for shutting down the operation of the burner, its ignition and the controller in the event the fire goes out so as to thus prevent the possibility of the ignition switch closing after the fire has gone out and additional oil and air have been discharged into the furnace, thus preventing ignition and explosion of such oil and air and providing a safety feature for the burner and ignition controller.

- With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawing, in which:

Figure 1 is a front elevation of a burner and ignition controller with my shut-down feature ent position; and

' Figure 6 is a perspective view of the operative connection.

On the accompanying drawing, I have used the reference numeral 10 to indicatean ignition switch housing and 12 to indicate a relay switch housing. A hub 14 is connected with the housings 10 and 12 for extension through the wall of a combustion chamber or stack of a furnace or the like.

A rotatable rod 16 extends through the hub 14 and a bimetallic coil 18 is connected at 20 to the hub 14 and at 22 to the rod 16 for imparting oscillation to the rod, depending on temperature changes within the combustion chamber or stack.

-An ignition switch arm 24 is pivoted at 26 in the housing 10 and is provided with an arm 28 connected by a link 30 with an arm 32 of the rod 16. The switch arm 24 carries leaf springs 34 and 36 having contacts 38 and 40. The contacts 38 and 40 are adapted to engage contacts 42 and 44. The contacts 40 and 44 are ignition contacts and are the only ones which need be referred to specifically in connection with the present invention. These contacts are connected in series with the ignition mechanism of the burner.

Magnet poles 46 are arranged adjacent the contacts 38, 40, 42 and 44 and act upon the switch arm 24 for causing snap action of the mechanism.

It will -be obvious that oscillation of the rod 16 will be imparted to the switch arm 24 for opening and closing the contacts, depending on temperature conditions of the stack which affect the bimetallic coil 18 to cause it to wind and unwind.

Within the relay switch housing 12 there is a relay coil 48 adapted when energized to attract an armature 50. The armature 50 is pivoted on a pin 52 and carries contacts 54 and 56 adapted to engage contacts 58 and 60, respectively. The contacts 54, 56, 58 and 60 are in circuit with the burner blower and oil valve of the burner so as to cause their operation when the relay switch is energized and stop their operation when it is de-energized. The relay coil 48 is included in circuit with a room thermostat so that the relay coil will be energized and de-energized, depending on room temperature. The foregoing description is general for a burner and ignition controller of the type shown in my co-pending application wherein the circuit and operation are fully disclosed,

In the operation of a burner, the fire may go out while the room thermostat is still in position for operation of the burner. There are several causes forextinguishment of a fire such as a slug of water in the oil, low oil supply permitting air to enter the oil line, a leak in the oil suction line, or a down draft in the furnace which causes the oxygen the furnace to be burnt out before an up draft can supply more oxygen, etc.

In the event that the control device is in operating p'ositionthat is, the relay switch is closed for causing air and oil to enter the furnace and the ignition contacts 40 and 44 are sepa-r rated because of the stack being, hot and the fire goes out for any reason whatsoever, the stack will cool down with the burner still in operation and the ignition contact will engage the contact 44 for re-establishing ignition, which of course would cause an explosion because of -the accumulated air and oil in the furnace. The main object of my present invention is to guard against such re-ignition and consequent explosion and shut down the operation of the burner until the cause for the shut-down has been remedied, whereupon the control device can be reset for automatic operation in the ordinary manner, as disclosed in my co-pending application.

To prevent re-ignition, it is necessary to provide a means to prevent the contact 40 from touching the contact 44 even though the switch arm 24 moves toward closed circuit position, while the relay contacts 54 and 56 are in closed circuit position. I therefore provide an operative connection for accomplishing this in the form of a lever 62 pivoted on a pin 64 and connected by a link 66 with the relay armature 50. The pivot pin 64 is supported by a bracket 68 and the lever 62 is provided with an arm .70 carrying an engager member 72 of leaf spring material. The engager member 72 has a head 74 adapted to engage the leaf spring 36 which carries the ignition contact 40, as shown in Figure 3, under certain conditions, which will be described in the operation of the device.

Practical operation v ment with each other because of the stack being cold. The closing of the relay switch moves the lever 62, the arm '70 and the engager 72 to the full line position of Figure 5. When the stack heats up, the contacts 40 and 44 will become separated for breaking the ignition circuit and the parts 24, 34, 36 and 72 will assume the dotted line position of Figure 5. Thereafter, when the room thermostat opens the circuit through the relay, a spring 76 draws the armature away from the relay coil 48 and at the same time moves the parts 62, 70 and 22 downwardly from the position shown by solid lines in Figure 5 about the pin 64 as a pivot. Then when the stack cools down, the ignition contacts 40 and 44 are re-eng'aged, but since the room thermostat is in open circuit position, ignition does not occur until the room thermostat is again in closed position. This is the normal cycle of operation of the device.

When the relay coil 48, however, is energized for holding the lever 62 in its raised position as shownin Figure 3 and subsequently the fire goes out while the room thermostat is still in closed circuit position, the stack cools down and the switch lever 24 moves to closed circuit position. The head 74 of the engager member 72, however, has assumed a position in the path of movement of the leaf spring 36 and thus holds it in the position shown in Figure 3 and in the dotted line position shown in Figure 4 with the contacts 40 and 44 separated.

The ignition therefore cannot be re-energized until after the cause for the fire going out has been remedied and the device reset for automatic operation.

Further operation of the control device will continue as inmy co-pending application so that a thermal cut-out breaks the control circuit after a predetermined period of time and shuts off all current to the entire system until such time as the trouble has been remedied. With the current shut ofi from the relay coil 48, it of course will return to open circuit position, thus pulling the lever 62 with it so as to allow the ignition contacts 40 and 44 to become engaged for their proper operation whenever the system is again put into operation. The entire invention resides in pre: venting movement of the ignition contacts to closed position while the burner switch is in closed position, which is a non-normal condition caused by the fire going out.

Some changes maybe made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it ismy intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

\ I claim as my invention:

1. A control structure comprising a switch including a switch arm and a contact leaf spring carried thereby, a burner switch, said switch arm and leaf spring being temperature actuated and means interposed between said switches for obstructing movement of said leaf spring to closed circuit position frorn open circuit position when said switch arm m yes to closed circuit position and while the seco r d switch is in closed position, said means being engageable with the edge of said leaf spring when said second switch moves to closed position before said leaf spring moves to open position and thereupon being constrained to assume its obstructing position as soon as saidleaf spring does moves to open circuit position.

2. In a control device, aswitch including a switch arm and a contact leaf spring carried thereby, a second switch, means for actuating said switch arm and leaf spring to closed circuit position, and means interposed between said switches for obstructing movement of said leaf spring to closed circuit position from open circuit position when said switch arm moves thereto and while said second switch is in closed circuit position, said means having a resilient portion carried thereby for normally obstructing movement of said leaf spring to closed circuit position but engaging an edge of said leaf spring for thereby permitting movement of said means but not said resilient portion to obstructing position when said switch arm and leaf spring are first closed and said second switch is closed thereafter.

MALCOLM E. HENNING. 

